"He's not a violent man," she said. "He's never hurt me or even made me feel afraid."

Now, the couple, who have been married for 10 years, said the separation is destroying the family.

"It's torn us apart," Adam Kearns told ABCNews.com. "I can't go home; I can't be a husband and a father. My goal is to get home, that's all that matters."

After the Feb. 20 incident, Kearns was diagnosed with REM Behavior Disorder, a condition in which people physically act out their dreams.

The night Kearns struck his wife, their 5-year-old ran into his parents' bedroom about 4 a.m., screaming with night terrors. His mother woke up, and the next thing she knew her husband began to beat her with his fist, according to her account in her frantic 911 call.

"He started yelling at me - I couldn't reason with him," Randi Kearns cried on the 911 tape. "It was like he was asleep. It was the weirdest thing - he's never hurt me in his life."

Doctors say Kearns may have had a "primal reaction" to his son's scream and lashed out, according to Kearns.

The Keizer Police Department told KATU-TV that they were forced to press charges when paramedics arrived and reported the nocturnal assault. Police said they are required by law to arrest people who commit an assault in their own home.

Kearns was jailed for three days and then released on the condition that he stay away from his wife, but he has been able to visit his children.

"She is my soul mate," he said. "She is the one person that God has blessed me with and the last person I would ever lay my hands on."

But the Marion County District Attorney's office is still charging Kearns with felony spousal abuse and the case is scheduled to be heard May 5.

"Our goal is to hold people accountable," said Oregon Assistant District Attorney Doug Hanson.

Kearns said he was evaluated by the Willamette Sleep Center, in Salem, Ore., after the incident.

Sleep experts say that periods of stress can trigger incidents of sleepwalking or violence.

Kearns was stressed, he said, after he accumulated $12,000 in medical debts while working a part-time job with no health insurance.

"I hadn't been sleeping very well for six weeks," Kearns said. "I was pretty exhausted."

Beyond the financial worries, the couple also lost each of their grandfathers this year, their 5-year-old just had surgery for sleep apnea and Randi Kearns' father is recovering from brain cancer surgery.

Her mother and stepfather had been living at the house with Randi Kearns, but have since moved to live with Adam Kearns.

As a boy, Kearns said he had night terrors and in the days leading up to the incident, he said his wife told him he had been talking in his sleep and moving around the bed.

REM behavior disorder is usually seen in much older adults. The most heinous crimes committed during sleep tend to occur in non-REM parasomnias.

Parks, a 23-year-old Toronto man with a wife and infant daughter, got in his car and drove 14 miles to the home of his in-laws. There, while still asleep, he stabbed to death the woman who called him the "gentle giant."

Sleepwalking is relatively common in childhood, but can be troublesome if it persists in adulthood.

About 15 percent to 20 percent of all children, both girls and boys, sleepwalk, according to the American Sleep Association. Usually it peaks around age 11 or 12 and rarely continues as they mature.

Surprisingly most violent sleepwalking occurs in the earliest part of the sleep cycle, during deep sleep, before REM (rapid eye movement) and dreams occur.

But in REM behavior disorder, sleepers like Kearns can react in direct response to a dream and hurt their bedmates.

In both REM and non-REM sleepwalking, eyes are wide open and sleepers are difficult to wake.

Usually, a sleepwalking session ends abruptly, leaving the person confused and disoriented upon waking, with no memory of the event.

Researchers say there is a genetic basis to sleepwalking -- children whose parents are sleepwalkers are two to three times more likely to go on to exhibit the same behavior.

The "architecture" of sleep looks like a skyline, according to Cartwright. As the brain begins to shut down all visual and audio input, the muscles relax and breathing is progressively slower and deeper.

In about 20 minutes the body is in deep sleep with the highest amplitude and slowest brain waves. It is during this time that walking and talking are most likely to occur. In children, those delta waves are accompanied by growth hormone.

But gradually, the deep cycle decreases and the waves have less amplitude, and after 30 minutes, the sleeper moves into the REM or rapid eye movement phase.

Body Is Supposed to be Paralyzed in REM Sleep

REM is characterized by a sudden and dramatic loss of muscle tone where the person is essentially paralyzed, except for the eyes, which dart like "ping-pong balls," breathing, and in men, erections.

It is also associated with dreaming and the blood pressure and breathing can be erratic.

Throughout the night, the brain moves between those two phases in 90-minute cycles, with deep sleep becoming shorter and REM periods longer.

The last REM period of the night comes six to seven hours later and it's "very long, very vivid, lots of color, lots of drama and lots of emotion," Cartwright said. "You go from a short preview of the coming attraction to a biggie and it goes from what is currently on your mind to long-term memories."

Falater's neighbor testified that he watched over his backyard fence as the father of two went inside his house to wash his hands, ordered his dog to lie down, then rolled his wife's body into the pool and held her head under water.

He had been trying to fix a faulty swimming pool pump, and defense lawyers suggested his wife may have interrupted him while he was trying again to fix the pump in his sleep, triggering a violent reaction.

If you or a loved one experience sleepwalking, doctors suggest finding a sleep clinic to determine the extent of the parasomnia. Specialists can recommend stress-reduction techniques and medications that can help the disorder.